diff --git a/readme.md b/readme.md
index 4da75e6..af99b87 100644
--- a/readme.md
+++ b/readme.md
@@ -2249,7 +2249,7 @@ PCBs and perfboard with optional components. The shape can be a rectangle with o
 | `pcb_accessories(type)` | List of accessories to go on the BOM, SD cards, USB cables, etc. |
 | `pcb_colour(type)` | Colour of the subtrate |
 | `pcb_components(type)` | List of components |
-| `pcb_grid(type)` | Grid if a perfboard |
+| `pcb_grid(type)` | Grid origin if a perfboard |
 | `pcb_hole_d(type)` | Mounting hole diameter |
 | `pcb_holes(type)` | List of hole positions |
 | `pcb_land_d(type)` | Pad around mounting hole |
diff --git a/vitamins/pcb.scad b/vitamins/pcb.scad
index f9aac64..0c5c11b 100644
--- a/vitamins/pcb.scad
+++ b/vitamins/pcb.scad
@@ -50,7 +50,7 @@ function pcb_parts_on_bom(type) = type[9];  //! True if the parts should be sepa
 function pcb_holes(type)        = type[10]; //! List of hole positions
 function pcb_components(type)   = type[11]; //! List of components
 function pcb_accessories(type)  = type[12]; //! List of accessories to go on the BOM, SD cards, USB cables, etc.
-function pcb_grid(type)         = type[13]; //! Grid if a perfboard
+function pcb_grid(type)         = type[13]; //! Grid origin if a perfboard
 function pcb_polygon(type)      = type[14]; //! Optional outline polygon for odd shaped boards
 function pcb_screw(type, cap = hs_cap) = Len(type[15]) ? type[15] : find_screw(cap, screw_smaller_than(pcb_hole_d(type))); //! Mounting screw type
 function pcb_size(type) = [pcb_length(type), pcb_width(type), pcb_thickness(type)]; //! Length, width and thickness in a vector